The Official Municipality Key, formerly also known as the Official Municipality Characteristic Number or Municipality Code Number, is a number sequence for the identification of politically independent municipalities or unincorporated areas. Other classifications for the identification of areas include postal codes, NUTS codes or FIPS codes.

The municipality key consists of five digits in Austria, which are generated as follows: The first digit designates the number of the Austrian state, the second and third digits designate the district, and the fourth and fifth digits designate the municipality.

In Germany the Official Municipality Key serves statistical purposes and is issued by the statistics offices of individual German states. The municipality key is to be indicated in instances such as changing residence on the notice of departure or registration documents. This is done at the registration office in every town's city hall.

The municipality key consists of eight digits, which are generated as follows: The first two numbers designate the individual German state. The third digit designates the government district (in areas without government districts a zero is used instead). The fourth and fifth digits designate the number of the urban area (in a district-free city) or the district (in a city with districts). The sixth, seventh, and eighth digits indicate the municipality or the number of the unincorporated area.

For example, the municipality of Ubay, Bohol has a code of 071246000 meaning region 07 (Central Visayas), province 12 (Bohol), munipality 46 (Ubay) with barangay code of zero signifying "not at this level"; whereas Bongbong, one of its constituent barangays, has a code of 071246007.

Note that province code is unique and independent of region code. All PSGCs are therefore unique.

A kommunkod (municipal code) is a numerical code given to all Swedishmunicipalities by the Swedish tax authorities. The code consists of four digits, the first two indicating which county the municipality is situated in, and the last two specific for the municipality.

The code system was introduced with the municipal reform of 1952. There were three different categories of municipalities at the time, which affected the number that they were allocated. Those with stad-status (cities) were given codes ending in 80 to 99, smaller towns (köping) 60 to 79 and rural municipalities 01 to 59. The county seats were allocated codes ending in 80.

As part of the reform in the early 1970s, the categorization of municipalities was abolished, but the code was in most cases preserved. When several municipalities were merged, the code for the biggest municipality was kept.